CONCLUSION:

Breathing re-education can change breathing patterns and increase chest expansion. This change leads to an improvement in CROM Positive consequences may result from the improvement in diaphragm contraction or reduced activity of accessory muscles.

There were large ranges of variation (in mm) in the obtained minimum and maximum values, and such variations were also reported in other studies8,6,24. Simon et al.13 observed a diaphragmatic value range from 0 to 85 mm, Houston et al.25 observed a range from 23 to 97 mm, Kantarci et al.27 observed a range from 25 to 84 mm and Boussuges et al.8 observed a range from 36 to 92 mm.

Suboptimal breathing patterns and impairments of posture and trunk stability are often associated with musculoskeletal complaints such as low back pain. A therapeutic exercise that promotes optimal posture (diaphragm and lumbar spine position), and neuromuscular control of the deep abdominals, diaphragm, and pelvic floor (lumbar-pelvic stabilization) is desirable for utilization with patients who demonstrate suboptimal respiration and posture. This clinical suggestion presents a therapeutic exercise called the 90/90 bridge with ball and balloon. This exercise was designed to optimize breathing and enhance both posture and stability in order to improve function and/or decrease pain. Research and theory related to the technique are also discussed.

Many muscles used for postural control/stabilization and for respiration are the same, for example: the diaphragm, transversus abdominis, and muscles comprising the pelvic floor.1–6 Maintaining optimal posture/stability and respiration is important and is even more challenging during exercise. Exercise increases respiratory demand (e.g. running) and limb movements (e.g. arms moving while standing still) increase postural demands for stabilization.3,7

Many factors are potentially involved with suboptimal respiration and suboptimal (faulty) posture and may be associated with musculoskeletal complaints such as low back pain, and/or sacroiliac joint pain.8 (Table 1)

Suboptimal Respiration and Posture

Decreased/suboptimal Zone of Apposition of diaphragm

Decreased exercise tolerance

Decreased intra-abdominal pressure

Shortness of Breath/Dyspnea

Decreased respiratory efficiency

Decreased expansion of lower rib cage/chest

Decreased appositional diaphragm force

Decreased length of diaphragm (short)

Decreased transdiaphragm pressure

Increased use of accessory muscles of respiration

Poor neuromuscular control of core muscles

Increased lumbar lordosis

Increased anterior pelvic tilt

Increased hamstring length

Increased abdominal length

Rib elevation/external rotation

Sternum elevation

Increased activity of paraspinals

Increased lumbar-pelvic instability

Low back pain

Sacroiliac Joint pain

Thoracic Outlet Syndrome

Headaches

Asthma

One of the most critical factors, often overlooked by physical therapists, is maintaining an optimal zone of apposition of the diaphragm.3,9–11 The zone of apposition (ZOA) is the area of the diaphragm encompassing the cylindrical portion (the part of the muscle shaped like a dome/umbrella) which corresponds to the portion directly apposed to the inner aspect of the lower rib cage.12 The ZOA is important because it is controlled by the abdominal muscles and directs diaphragmatic tension. When the ZOA is decreased or suboptimal, there are several potential negative consequences. (Table 1) Two examples include:

Inefficient respiration (less air in and out) because the transdiaphragmatic pressure is reduced.11 The smaller the ZOA, there will be less inspiratory action of the diaphragm on the rib cage.11

Diminished activation of the transversus abdominis which is important for both respiration and lumbar stabilization.11,13

The incidence of LBP has been documented to be as high as 30% in the athletic population, and in many cases pain may persist for years.15 Low back pain is frequently correlated with faulty posture such as an excessive lumbar lordosis.16–18 Excessive lumbar lordosis may be associated with over lengthened and weak abdominal musculature.18–20 Poor neuromuscular control of core muscles (transversus abdominis, internal oblique, pelvic floor and diaphragm) has been described in individuals with SIJ pain21 and in individuals with lumbar segmental instability, potentially adversely affecting respiration.22

Richardson et al.27 describe coordination of the Transversus abdominis and the diaphragm in respiration during tasks in which stability is maintained by tonic activity of these muscles. During inspiration, the diaphragm contracts concentrically, whereas the transversus abdominis contracts eccentrically. The muscles function in reverse during exhalation with the diaphragm contracting eccentrically while the transversus abdominis contracts concentrically. Hodges et al. noted that during respiratory disease the coordinating function between the transversus abdominis and diaphragm was reduced.6 Thus, it is also possible that faulty posture such as over lengthened abdominals and excessive lordosis could reduce the coordination of the diaphragm and transversus abdominis during respiration and stabilization activities.

O’sullivan et al.21 studied subjects with LBP attributed to the sacroiliac joints and compared them to control subjects without pain. O’sullivan et al. compared respiratory rate and diaphragm and pelvic floor movement using real time ultrasound during a task that required load transfer through the lumbo-pelvic region (the active straight leg raise test). Subjects with pain had an increase in respiratory rate, descent of their pelvic floor and a decrease in diaphragm excursion as compared to the control subjects, who had normal respiratory rates, less pelvic floor descent, and optimal diaphragm excursion. While O’sullivan et al. concluded that an intervention program focused on integrating control of deep abdominal muscles with normal pelvic floor and diaphragm function may be effective in managing patients with LBP,21 they did not describe strategies or exercises to achieve this goal.21

While the role of the Transversus abdominis in lumbar stability is well documented, less well known is the role of the diaphragm in lumbar stability. While the primary function of the diaphragm is respiration, it also plays a role in spinal stability.3,28

The right hemidiaphragm attaches distally to the anterior portions of the first through third lumbar vertebrae (L1-3) and the left hemidiaphragm attaches distally on the first and second lumbar vertebrae (L1-2).29 This section of the diaphragm is referred to as the crura. Of interest is the asymmetrical attachment of the diaphragm with the left hemidiaphragm attaching to L1-2 and the right portion attaching to L1-3.

During the inhalation phase of ventilation, the dome of the diaphragm moves caudally like a piston creating a negative pressure in the thorax that forces air into the lungs. This action is normally accompanied by a rotation of the ribs outward (external rotation) largely in part due to the ZOA.12 (Figure 1) Apposition is a term that means multiple layers adjacent to each other.33 The normal force of pull on the sternal and costal portions of the diaphragm would produce an internal rotation of the ribs. The ZOA creates an external rotation of these ribs primarily because the pressure in the thoracic cavity prevents an inward motion. The crural portion of the diaphragm assists the caudal motion of the dome. It also pulls the anterior lumbar spine upward (cephalad and anterior). Additionally, the abdominal muscles and pelvic floor musculature are less active to allow visceral displacement due to the dome of the diaphragm dropping. With exhalation, this process is reversed. Abdominal muscle activity compresses the viscera in the abdominal cavity, the diaphragm is forced cephalad and the ribs internally rotate. As exhalation becomes forced as during exercise, abdominal activity (rectus abdominus, internal obliques, external obliques, and transversus abdominis) will be increased.34–36

When the ZOA is optimized, the respiratory and postural roles of the diaphragm have maximal efficiency.37 In suboptimal positions (i.e. decreased ZOA), the diaphragm has a decreased ability to draw air into the thorax because of less caudal movement upon contraction and less effective tangential tension of the diaphragm on the ribs and therefore lower transdiaphragmatic pressure.38 This decreased ZOA is accompanied by decreased expansion of the rib cage, postural alterations, and a compensatory increase in abdominal expansion.12 (Figure 2)

One such adaptive breathing strategy would be to relax the abdominal musculature more than necessary on inspiration to allow for thoraco-abdominal expansion. This situation leads to decreased abdominal responsibility while breathing and can contribute to instability. This would reflect more upper chest breathing and less efficient diaphragm activity. If the body maintains this position and breathing strategy for an extended period of time, the diaphragm may adaptively shorten and the lungs may become hyperinflated.37,39,40 Hyperinflation may also contribute to over use of accessory muscles of respiration such as scalenes, sternocleidomastoid (SCM), pectorals, upper trapezius and paraspinals in an attempt to expand the upper rib cage.41–44Again, without an optimal dome shape/position of the diaphragm or an optimal ZOA the body compensates to get air in with accessory muscles since the more linear/flat/short diaphragm is less efficient for breathing.32

The patient/athlete is asked to hold the balloon with one hand and inhale through his/her nose with the tongue on the roof of the mouth (normal rest position) and then exhale through his/her mouth into the balloon. The inhalation, to about 75% of maximum, is typically 3-4 seconds in duration, and the complete exhalation is usually 5-8 seconds long followed by a 2-3 second pause. This slowed breathing is thought to further relax the neuromuscular system/parasympathetic nervous system and generally decrease resting muscle tone. Ideally the patient/athlete will be able to inhale again without pinching off the balloon with their teeth, lips, or fingertips. This requires maintenance of intra-abdominal pressure to allow inhalation through the nose without the air coming back out of the balloon and into the mouth.

When the exercise is performed by the patient/athlete with hamstring and gluteus maximus (glut max) activation (hip extensors) the pelvis moves into a relative posterior pelvic tilt and the ribs into relative depression and internal rotation. This pelvic and rib position helps to optimize abdominal length (decreases) and diaphragm length/ZOA (increases).

In order to assess the loads placed on a spine during various positions, Rohlmann, et al. (2011) looked at various seating positions.4 They found the implant force increased 48 percent for 15 degrees flexion and decreased 19 percent for 10 degrees extension of the trunk. Placing the hands on the thighs reduced the loads by 19 percent, on average, compared to having arms hanging at the sides.

Dreischarf, et al. (2010) also found that reduced spinal load during sitting can be achieved by supporting the upper body with the arms.5

A study by De Carvalho, et al. (2010) compared lumbar spine and pelvic posture between standing and sitting via radiologic investigation. Lumbar lordosis and sacral inclination decreased by 43 and 44 degrees, respectively.6 This shows that with respect to sitting posture, to goal should be to maintain or prevent a reduction of the lumbar lordosis.

One study found 40-percent higher cervical extensor activity in the slouched posture. More neutral sitting postures reduce the demand on the cervical extensor muscles.7 Education on maintaining a neutral sitting posture can offset the detrimental effects.

A study by Caneiro, et al. (2010) showed that slumped sitting was associated with greater head / neck flexion, and increased muscle activity of the cervical erector spinae.9 Adjustments to seat angle and lumbar roll can also significantly effect head and neck posture.

A study by Horton, et al. (2010) found that the degree of angulation of the backrest support of an office chair, plus the addition of a lumbar roll support, are the two most important seat factors that will benefit head and neck postural alignment.10

A study by Bullock, et al. (2005) looked at how sitting posture can affect range of motion and pain for those with shoulder impingement.11 An erect posture appeared to increase active shoulder flexion, although there was no difference in shoulder pain between an erect and slouched posture.

Finley, et al. (2003) found that an increased thoracic kyphosis from a slouched posture can significantly alter the kinematics of the scapula during humeral elevation.12

And Kebaetse, et al. (1999) found that a slouched posture is associated with a 16.2 percent reduction in arm horizontal muscle force.13

A recent study by Dunk, et al. (2009), out of the University of Waterloo, evaluated whether the intervertebral joints of the lumbosacral spine approach their end ranges of motion in a seated posture.15 In upright sitting, the L5-S1 intervertebral joint was flexed to more than 60 percent of its total range of motion. In a slouched posture, each of the lower three intervertebral joints approached their total flexion angles. This shows an increased loading of the passive tissues (time-dependent «creep»), which may contribute to low back pain from prolonged sitting.

A study by Reeve, et al. (2009) assessed the thickness of the TrA in various postural positions. Thickness was significantly greater in standing and erect sitting than in a slouched or sway-back standing position.16 The authors concluded that lumbopelvic neutral postures have a positive influence on spinal stability compared to equivalent poor postures.

A study by Claus, et al. (2009) looked at the effect of various postures on regional muscle activity.17 For the deep and superficial fibers of lumbar multifidus muscles, the least muscle activity occurred during a flat posture, which was similar to a slump posture. The most activity occurred in a short lordosis position; there was also more activity in the obliquus internus.

A study by Dolan, et al. (2006) provided evidence that a slouched posture of 5 minutes’ duration can increase reposition error.18 Proprioceptive control is known to be valuable in spinal stability. The fact that reposition error can occur within as little as 5 minutes of «slouched» posture suggests the importance of postural education in decreasing proprioceptive loss and injury.

It can be concluded that patients with chronic neck pain present weakness of their respiratory muscles. This weakness seems to be a result of the impaired global and local muscle system of neck pain patients, and psychological states also appear to have an additional contribution. Clinicians are advised to consider the respiratory system of patients with chronic neck pain during their usual assessment and appropriately address their treatment.